Color stable resin containing indene polymers



email). 16, 1941 COLOR STABLE RESIN CONTAINING INDENE POLYMERS William H. Cannody, Pittsburgh, Pa, asslgnor to The Neville Company, Pittsburgh, Pa, a cor pontion of Pennsylvania No Drawing. Application May 21, 1588, Serial No. 209.389

6' Claims.

This invention relates to the control and prevention of the deleterious quality of "after-yellowing o! coumarone-indene resin.

As is well known, coumarone-indene resin, commonly known in commerce simply as coumatone or paracoumarone rain, is a synthetic resin produced by the polymerization of bodies contained in crude solvent naphtha. or its equivalent container of polymerizable substances. Coumarone-indene resin has many qualities rendering its use desirable in paint, varnish and other coating compositions. However. these resins are subject to the phenomenon or alter-yellowing".

which has militafed against their use with spar varnish and other clear, untinted, coating compositions, as well as in coating compositions comprising white, or light-colored. Pigments. yellowing manifests itself by a progressive darkening-incolonsothat withagingaresinwhich is initially of light color. or colorless, turns yellow, yellowish-brown, or even brown. This discoloration occurs in solid coumarone-indene resin. as such, and to some extent in solutions of theresimbutitisparticularly prominentin-fllms of the or in films ot coating compositions -comprising the resin. In connection with my Amaiorobiectotthisinventionistoprovide Afteror the resin. I have discovered that that supposition is erroneous and that although afteryellowing is the result of a reaction or development initiated by the action of oxygen, it is of more complex nature than supposed heretofore. I have found that it is the indene content of coumarone-indene resin which is primarily responsible for the phenomenon of after-yellowing, and that coumarone, considered by itself, is substantially immune to after-yellowing, although it may contribute to and be an important, it not the maior, cause of after-yellowing in indene resin.

I have discovered further, and it is upon this that my invention is in large part predicated, that the after-yellowing poten'tialitymf coumarone-indene resin may be controlled, and even eliminated, at least for commercial requirements, by hydrogenation 0! a solution of the resin in the presence of a suitable hydrogenation catalyst,

Such treatment does not substantially affect the melting point of the resin, and does not depreciate its valuable characteristics, such as inertness toward acids and alkalies. but it does reduce or substantially eliminate its after-yellowing potentiality. Concurrently therewith there is improvement in the solubility of the resin in hydrocarbon solvents, which is, of course, desirable although, as will be understood, a primary desideratum is control of after-yellowing. I have discovered also that, strikingly enough, extensive hydrogenation of the resin is unnecessary to achieve the objects of the invention. It appears that actually the tendency to after-yellow may be repressed or eliminated by hydrogenation amounting to only a fraction of that theoretically posible, Such control of this disadvantageous property of these resins is explainahle by a consideration of the structure of the indene polymer.

'While various structural formulae have been predicated for the indene polymer, it is recognized that the indene monomer is represented by the structural formula:

Evidence of the existence of a cyclopentadiene radical, or structure, in the indene monomer is obtainable from color reactions oi the indene Y monomer with aldehydes and ketones. By reacting aldehydes and ketones with the indene'monomer, colored bodies are produced which are typical of the iulvenes obtained with cyclopentadiene and the same reagents. Thus, cyclopentadiene reacts with, for example, ketones, with production oi intensely colored bodies accordingly to the reaction:

In so far as the indene monomer is concerned, the same reaction is possible:

c----cn= indene polymer Terminn unit the polymer The terminal indene unit is as shown, irrespcctive oi the number of indene units comprised in the polymer, and irom what has been said it will be seen that it, too, is capable, theoretically, of reacting with aldehydes and ketones to Produce deeply colored reaction products.

I have proved this to bethe case by reacting indene polymer with aldehydes and with ketonu. This procedure developed the color reactions means typical of reaction of each aldehyde and he tone used with cyclopentadiene, thus proving that in the indene polymer there is a cyclopentadiene structure in reactive position.

In making these tests, I made an approximate 10 per cent solution of coumarone-indene resin in an aromatic solvent. To this solution, I added, without heating, a small amount of acetone, together with a few drops oi'an alcoholic solution. or sodium hydroxide as an accelerator. At normal room temperature, a color reaction developed immediately and continued to intensity for a period of approximately one-half hour, when the liquid was a deeply-tinted brownish-red color. The literature shows that'this color reaction is typical of the iulvene development produced by reaction of acetone with' cyclopentadiene, and with the iulvene development occurring in the color reaction of acetone with the indene monomer. This I checked by actual test, and obtained the results given in the literature, and as obtained in the color reaction occurring with the polymer. The only observable difierence in the color reaction between acetone and coumarone-indene resin, acetone with cyclopentadiene. and acetone with indene monomer, was slight diiierences in a color intensity.

I also checked by adding acetaldehyde, under identical conditions, to the resin solution, to cyclopentadiene, and to indene monomer. The coloration was in each case a relatively deep yellowish-brown. The reaction proceeded with a relatively great rapidity, at room temperature,

which, in correlation with the depth of color obtained, showed that the coloration was due to iulvene development, rather than aldehyde polymerization.

Having thus established that coloration of the indene polymer may occur through reactions characteristic of fulvene development in a cyclopentadiene structure, it is reasonable to ume that in an indene polymer there is present at least one cyclopentadiene structure susceptible of producing iulvene' bodies. As shown above, the terminal indene unit of the polymer presents such a radical in which a double bond present outside of the aromatic nucleus is linked by a carbon atom to the double bond of the pair of carbon atoms shared with the aromatic nucleus oi the terminal unit. thus providing a true cyclopentadiene radical capable of the typical fulvene reaction. This may be represented as follows, considering only the terminal unit of the On this basis the phenomenon of after-yellowing is readily explainable, the necessary aldehyde or'ketone beingproduced by oxidation of indene or coumarone polymer molecules, either or both.

with reaction oi other indene polymers thereano e-rs cordance with the roliowing structural formulae:

Terminal unit of indene polymer I II Such an oxidation product may react, through one or the other of the C= linkages, with the cyclopentadiene radical of the terminal unit of an unoxidized indene polymer in the manner represented above. The coumarone polymers may likewise be oxidized to provide products similarly reactive. In both cases such reaction-would be productive oi colored bodies and would explain the after-yellowing of these resins.

The explanation given is thus wholly consistent with the fact of auto-yellowing in an indene film. It is also consistent with the rapid discoloration oi the higher fractions of a waterwhite, freshly distilled, indene fraction of crude solvent naphtha. The action of oxygen in the foregoing manner is further demonstrable in the case of a film of pure coumarone-indene resin. It has been noted that the after-yellowing is asurface phenomenon because it a yellowed be washed with a solvent for the resin, the underlying portion or the film is found to be unyellowed. but exposure of such a clean surface 01' resin leads to gradual yellowing of the surface so exposed.

Such discoloration is encountered also is the case or coumarone-indene resin heated with oils. e. g., tun oil, in making a cooked varnish, andin the case of a coumarone resin worked up with oils, by solution of the resin and without heating. In these cases the varnish is much darker than any 01 the ingredients. Here the resin is in the presence of aldehydes and ketones, andthe mass is subject consequently to a rapid and intensified discoloration.

Aldehydes and/or ketones being present either byinitislinclusiomorinthecascoi apureresln illmbythesctionoioxygen. thciulvencorother color dcvelopmentmay take place in typical mannor. The ei'lcct of oxidation on an indeoc poly- Although the foregoing postulates explain satisfactorilythecauseandmodcolcuringamyellowinginthcseresinnldonotlimitmyseli' to such explanations.

Turning now to the operating conditions involved in the practice of the invention. important benefits now from hydrogenation or the resin in solution. For reasons pointed out hereinafter it is desirable to hydrogcnatc at temperatures above atmospheric, and to bydrogcnate the resin in solution. I! the resins be used disadof serious and objectionable nature may be encountered, such as changes in molecular magnitude, with deprec ation of resin properties. On the other hand, the use of solutions confers stability to heat at the temperaturesdesirable in practice, and. such solutions are freed from catalyst more readily than is the case with fused resin. The factor oi heat stability becomes increasingly important as the molecular weight oi the resin increases.

Most suitably the solvent is one which is inert to hydrogenation because of more ready control of the reaction and for hydrogen economy. Suitable examples are cyclohexane and cycloparaflins,

' although petroleum solvents or similar nature,

merfllmisnohtberdormdirectlytoproduceby.

oxidation an ingredient which itself colors the illm,butismerelytoproduoconcormorointcrmcdiatcoompoundscapablootproducingbyroacflonwithtbccyclopentodimcstruchrrootthc end unitoftbemdmcpolymcnacolorbody premmsblyotiulvme character. Within the. abovemyreszfltsarcoonsistcnt.

Thcloresoinsrccotlouscxplainalsothotact that attcr-ycllowinsml-rbecontmllcdwithout extensive mtoprcvcnttulvenctormationitisnccessnryonlytosahn-atconcoithoc=clinhsesolthc such as petroleum benzine, may be used, especial- 1y where the hydrogenationis conducted at superatmospheric temperature. For the same reasons it is best that the solution be free, or sub stantlally so, from other materials capable or substantial hydrogenation.

Various catalysts are known capable oi electing hydrogenation, and while they might be used I prefer to use the metallic hydrogenation catalysts, particularly nickel. have found that desirable results are to be with the so-called Raney nickel catalyst. This is prepared from a nickel aluminum alloy to, say, approximately 200-mesh fineness; finely-divided alloy is then sprinkled into a 10 cent sodiumhydrorlde solution, which dissolves the aluminum. The metallic nickel. which remains as a sponge powder, is then by successive washings with water, and: isint'roduccd into" a hydrocarbon, such as; solvent. and the water boiledoil. In this i-zondit'ion, submerged in a hy and protected throushout its preparation lrom spo se is an emcient catalyst, and is for that reason used by me in conducting hydrogenation;

Hydrogenation of the resin begins at normal room tcmperamre, but the rate isso slow that for reasons of economy it is desirable to operate at super-atmospheric The optimum operating temperamrenowappears-tobeabout 200or205' 6.: andattemper'aturcsotthcordsr or 225' or 250. 6. obi'ectlonsblc actions are onoountcrcdsuchnschanses inmolceular moon poses of the invention the eiiect oi pressure change is to alter the rate of reaction and equilibrium point. Working with pressures from atmospheric up to rather high pressures, I have' found that hydrogenation eiiective to repress after-yellowing is achieved. For some purposes it is desirable to render the resins substantially non-yellowing, and for such purposes rather low pressures may be used. As the pressure increases there is an increasing tendency toward hydrogenation of the aromatic nuclei of the resin molecules. and although this is unnecessary in preventing after-yellowing, it is desirable because it results in improved solubility in hydrocarbon solvents. In general, low pressures favor maximum repression of after-yellowing, at least from commercial standpoints, with minimum improvement in solubility characteristics, while high pressures afford maximum improvement in solubility, but with less than complete elimination of the tendency to after-yellowing. However, for many purposes resins hydrogenated at high pressures are satisfactorily resistant to after-yellowing. 1 now prefer to operate at pressures of, say 800 to 1,200 pounds.

The first phenomenon attributable to hydrogenation is one of bleaching colored bodies initially present in the resin. This bleaching effect does not result from any substantial hydrogen-modification of the resin molecules, but mereb' from destruction of pre-existing color structures in the resin. In other words, such destruction does not depend chemically upon the introduction of hydrogen into the resin molecules capable of after-yellowing, such molecules being fully as capable of after-yellowing after bleaching as before. Color stabilization is, there- !ore, not eiiected by a mere bleaching treatment, and upon subjection to sunlight and atmospheric oxygen the development of the coloration known as after-yellowing begins, and proceeds as though the resin were untreated. Mere bleaching is of utility only to lighten the color of resin stocks which have in storage developed such deep coloration as to appear unattractive for sale even though the resin is purposed for such uses that afi.l'-'8HOWL'1Z is a matter of no practical importance.

The second phenomenon attributable to hydrogenation of the resin is color stabilization, i. e., an effect resulting from hydrogen-modification oi the polymer molecules in such manner that the tendency of the resin to go through chemical changes resultant in "after-yellowing" is in practical eitect inhibited, andfor the purposes of this invention this is the major and most important consequence of hydrogenation, and that sought primarily.

A third phenomenon attributable to hydrogenation of the resin is increased solubility of the resin, and specifically increase in solubility of the resin in petroleum solvents.

simple bleaching of pre-existing color bodies is attained readily and quickly, at atmospheric pressure, but as noted, this does not overcome fl'iy wina. If a double bond of the terminal cyclopentadiene radical could be saturated, to the exclusion of other portions of the molecule. 2 pounds of hydrogen would suillce to eliminate after-yellowing in 800 pounds of resin. However, such selective hydrogenation is not attainable, and some hydrogenation oi the aromatic nuclei occurs, and although this expenditure 0! hydrogen has no bearing on after-yellowing, it is compensated (or by increased solubility,

As exemplifying the practice oi the invention, reference may be made to the tests now to be described.

Test A.--In this test 50 gm. 0! cournaroneindene resin of 160 C. melting point were dissolved in cc. of petroleum benzine of to C. boiling point. The solution was placed in a l-quart capacity steel bomb with 50 gm. of Raney nickel catalyst. The bomb was flushed out with hydrogen and then charged therewith to a pressure 'of 310 pounds, following which it was heated gradually. At about 130 C. the rate of hydrogen absorption exceeded the total gas and vapor pressure, and the pressure dropped rapidly. The test was conducted for 20 hours at a maximum temperature of C. and a maximum hydrogen pressure of about 300 pounds (total pressure 380-390 pounds), hydrogen being recharged three times when the total pressure in the bomb fell towards 200 pounds. After the solution had cooled it was filtered, to separate the nickel, and the resin was recovered from the filtrate by distillation of the solvent. It was very light in color, and was not subject to after-yellowing. For instance, after 65 days it showed no change in color. In contrast, the same resin untreated was yellow in about 3 days, and was very brown after 65 days. The melting point of the resin was not changed observably, but itssolubility was improved from +65 C. to -14 C.

Solubility determinations reported herein are made by dissolving 5 gm. of resin in 20 gm. of Stoddard solvent naphtha, using gentle heating. The solution is then cooled and the temperature at which resin is deposited from solution is noted. Where a range is reported, the higher tempera ture is that at which the solution exhibits tur' bidity, and the lower that at which definite deposition of resin is observable.

Test B.-Th'e bomb was charged with 100 gm. of C. M. P. resin, 150 cc. of petroleum benzlne, and 100 gm. of Raney nickel catalyst. and warmed slowly after charging hydrogen to 130 pounds pressure. In 10.minutes the pressure fell to 65 pounds, and to zero in less than 40 minutes, when hydrogen was recharged. The

test was conducted 13 hours at a jig: drogen pressure of 130 pounds, a maximum temperature oi 100 C., and with a total or 5 re chargings with hydrogen. The resin was recovered as described in Test A. The melting point was unchanged, but the yellowing tendency was but 15 per dent of that or" the untreated resin. The solubility was changed from 59-56 C. to 3543 C.

Relatise yellowing tendency, as just referred to, is determined by a standardized procedure in which there is used as a standard a high grade unhydrogenated coumarone-indene resin having a melting point of C., and an initial color depth of 1.5. A illm of this resin is deposited on a glass slide at normal room temperature from a 20 per cent toluol solution of the resin, the solution being allowed freely to spread tor evaporation. The film is then subjected to ultraviolet light of maximum intensit for a period of 5 hours, which produces maximum afteryellowing. This is taken as 100 per cent yellow- This standardized constant of color intensity is translated into conveniently usable relative unitsof color intensity. To do so two tubes, are mounted in parallel vertical adjacency. tubes have flat bottoms and are so mountedthat glass slides may be introduced beneath them. Aneyepiecsoverthetubesbrlngsthe slideimagesseenthroughthetubebottomsvisualiy intoapparent contact with each other.

The standard slide yellowed by ultra-violet light is inserted beneath one tube, and distilled waterisintroduced intothe tubeupto acouvenient level therein. ,An unexposed slide is introduced beneath the other tube, and into thissecond tube there is introduced a solution of arbitrarily selected coloration. In this method thereisusedasolutionoiioi-potasshun dichromate in -1 litre oi distilled water. which aiiords a standard of constant color intensity. This solution is introduced into the second tube until it has reached such level that the color depth isapparently uniform for the two tubes. The space between the dichromate level and the bottom of the tube is then graduated, the total height of the column being given the value of 100: and desirably graduation in the same units is continued above the level the dichromate column to provide for evaluation of color intensity exceeding that of the resin which has been made the standard.

As noted beiore. a direct exposure to ultraviolet light for a period oi 5 hours substantially exhausts th'e after-yellowing potentiality oi the resin, any increase in color intensity which it is possible to develop thereafter being negligible.

In evaluating the yellowing potentiality oi a hydrogen-modified resin. two tubes 0! which one is provided with the standard graduations are used. Duplicate slides of the hydro n-modiiiedresinaremadeandoneoithemisupowd to ultra-violet li ht for a period of 5 hours.

Theyarethenplacedbeneath'thetubeatheunexposed slide being placed beneath the tube which is graduated, and distilled water being putinto the tube overlying the exposedslide.. The yellowing value oi! the resin isthen obtained by reading on the ted tube the height oi the standardized dichromate solution which produces an apparent uniiormity in-color between the un resin and the exposed resin. This Elves the relative yellowing potentiality or any particular resin provided the exposed and unexpcsedslidesmustbcoithe sameresin.

The following experiments are illustrative also of variations in operating, conditions and how theymeybevarledtocontrol the results. These.

Sample nmfsdubmu Yellowing o m-ss loo is ss-sc n hstreatcdrednwasotimpcrccptibiecclori Sample Hours Solubility Yellowing eo-sc ii!) 0947 82 -43 68 35-33 45 M 30 27-05.

This illustrates the eflect oi increase in pressure in improving solubility. Relatively the after-yellowing potentiality was somewhat greaterth'an thato'i'theresinoi'lstqbuttheresin was of acceptable grade as non-yellowing because on the resin scale the color was substantially less than 0.5 after exposure to ultra-violet light.

In other tests the treatment produced resins of greatly reduced or commercially non-yellowing tendency with solubilities as low as C. Likewise, perfectly satisfactory results may be had with lower proportions of catalyst. say as little as 3 per cent based-on the resin weight.

Test E.--In yet another test comparable results were had with a resin of 160' C. H. P., hyo enated at a maximum temperature of 200 C. and presure of 1,300 pounds. Alter 20 months the treated resin remained virtually colorless.

Test F.--This involved a high molecular weight resin made from crude solvent naphtha containing about 60 per cent by weight of idene. 2,000 cc. oi the naphtha were diluted with 400 cc. of carbon tetrachloride and the mixture was treated at room temperature with cc. of a 20 per cent solution of such in CCis. After standing over night tlm viscous mixture was thinned with 600' cc. of carbon tetrachloride and then poured in a thin stream into 12,000 cc. of methanol with viov lent stirring. The precipitated resin was filtered.

dissolved in benzine, and reprecipitated, this purliying step being effected a total oi' four times.

This resin had a melting point of 237' C.,

. which indicates a molecular weight of about 2.500.

It was not soluble in Stoddard naphtha at the boilingpoint. 100gm.orthereslnwith cm; 0! cyclohexane and 50 gm. of Fancy nickel were placed in the bomb and hydrogenated successfully in accordance with the invention. with a maximum bomb presure oi 1,950pmmds (initial hydrogen pressure at room temperature was 1,270 poimdshandatcmperatureoiabout 200C. ThetestwasconductediorShours. The resmwascolorlmitssolubilitywssim'Q nd. especially noticeable was the fact that-it became solubleinpetroleumsolventssndlinseedoilal thoughtheuntreakdrennwasnotsoiublein them. Thsmeltingpointwasraisedatewdegreesbythetreaiznent.

'Whilelihave,,thepe- 'eiiect of continued moderate temperature, and moderate Inanyevent, thefims or trestmentischosenwithrcgardtopruun-sand to-the extent necessary to develop the desired resistance to alter-yellowing. In this connection it should be emphasized that it is saturation of the color-forming structure, presumably a double bond of the cyclopentadiene structure in the terminal indene unit, which it is necessary to effect. It is not necessary in order to attain repression 'or elimination of after-yellowing that any other point in the indene molecule be hydrogenated. It is undesirable from the viewpoint of producing a commercially non-yellowing coumarone-indene resin that any other point of the molecule be hydrogenated, and for this purpose extremely high pressures and temperatures are ordinarily not necessary. However, as indicated above, by appropriate correlation of time, temperature and pressure, the objects 01' the invention may be attained while at the same time effecting other advantageous results.

The resin obtained as a product 01 hydrogenation is not subject rapidly or in substantial degree to after-yellowing. This is proven by the clear comparatively colorless appearance of the resin after continued exposure to light, both in lump and as spread in a film, in direct comparison with unhydrogenated resin identical source similarly exposed. I wish here to emphasize the fact that I produce a coumarone-indene resin which has been deprived of its yellowing potentialities, and that this resin is definitely hydrogen-modified coumarone-indene resin, usable for all the purposes to which coumarone-indene resin of previous production may be put, aswell as more desirable for certain uses. Hydrogenation,

as above described, not only produces a comarone-indeneresin i'reed from the undesirable quality or potential yellowing, but also results in decolorizing coumarone-indene resin in which color has developed.

From what has been said it will be appreciated that the invention is applicable not only to coumarone indene resin, but also to resin essentially composed of polymerized indene because it is the indene polymer.molecule that is essentially responsible for after-yellowing. By eliminating the color-forming power oi a structure oi that molecule by hydrogenation, probably by partial or complete saturation of a iulvene-iorming linkage, throughout the indene polymer molecules of the resin it is rendered non-yellowing, and by partial destruction the after-yellowing power is reduced pro tanto. This results also in elimination 01 the darkening encountered heretofore in making varnish and the like, as explained above. The hydrogenation may occur according to one or the other of the following formulae:

aaeaeve It is not known positively whether such hydro.- genation does occur, or whether one or all three possibilities are realized, but all of them will act a to destroy the color-forming potentiality of the untreated resin, and from my investigations I have reason to believe that some such mechanism is involved.

Coumarone may react similarly; for instance,

H i H I ooumarono polymer The other possibilities represented for indene are likewise present.

From what has been said it will be apprehended that various'modiiications are permissible in the practice of the invention. For instance. the resin may be subjected to repeated hydrogenation, as with fresh lots of catalyst. and this may be desirable with batches oi. resin which may be recalcitrant to elimination of after-yellowing in consequence of a single treatment.

This application is a continuation-in-part of my copending application Serial No. 1,897, filed January 15, 1935. Claims generic to the subject matter disclosed and claimed herein are contained in my copending application Serial No. 209,372 filed concurrently herewith and likewise a continuation-in-part of my aforesaid application Serial No. 1,897.

According to the provisions oi. the patent statutes, I have explained the principle and manner of practicing my invention, and'have described what I now consider to be its best embodiment. However, I desire to have it understood that, within the scope or the appended claims, the invention may be practiced otherwise than as'speciiically described:

I claim:

1. That method or treating resin material containing indene polymer to reduce after-yellowing thereof, which comprises providing a solution or said resin material, adding a metallic hydrogenation catalyst to said solution, subjecting the solution with agitation to the action of gaseous hydrogen at a tempertaure of about 150 to 225 C. and under a pressure 01! about to 2.000 pounds per square inch and thereby hydrogenating said material and rendering it resistant to after-yellowing.

2. That method of treating resin material containing indene polymer. to reduce after-yellowing thereof, which comprises providing a solution of said resin material in a solvent substantially inert to hydrogenation, adding a metallic hy genation catalyst to said solution, and subjecting the solution with asitation to the action of saleous hydrogen at a temperature of about to 200' C. and at a pressure of about 180 to 2,000 pounds per square inch and thereby hydrogenating said resin and converting it to a hydrogenated form in which after-yellowing is sub- 3. A method according to claim 2, said catalyst being metallic nickel.

4. A method according to claim 2, said catalyst being metallic nickel and the pressure being about 800 to 1,200 pounds per square inch.

5. That method 0! treating resin material cont m-in: indene polymer which comprises providing a solution of said resin material in a solvent substantially inert to hydrogenation and substantially free from substances other than said resin material capable of substantial hydrogenation, adding a metallic hydrogenation catalyst to the solution and subjecting the solution with agitation to gaseous hydrogen at a temperature of about 150 to 205 C. and at a pressure of about 800 to 1,200 pounds per square inch and thereby converting said resin to a form in which afteryellowing is substantially eliminated and solubi1- ity in hydrocarbon solvents is improved.

6. A method according to claim 5, said resin being coumarone-indene resin.

WILLIAM CARMODY.

CERTIFICATE OF CORRECTION. Patent No. 2,266, 675. December 16, 19 41. WILLIAM H. CARMODY.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follov vs: Page 14., second column, line 12, for "150 C. read "150 C.-; page 5, secqnd column, line LLO, for "idene" read indene-; page 6, second-columh, line 15, in the formula, for "CH read "CH and that the said Letters Patent should be read with this correction therein that the same may conform to the rec 0rd of the case in the Patent Office.

Signed and sealed this 5rd day of March, A. D. 191;,2.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents. 

